function validateContactForm() {

	

	if(document.getElementById("txtForename")) {

		if(document.getElementById("txtForename").value == "") {

			alert("Please enter a first name");

			return false;

		}

	}

	

	if(document.getElementById("txtSurname")) {

		if(document.getElementById("txtSurname").value == "") {

			alert("Please enter a surname");

			return false;

		}

	}

	

	if(document.getElementById("txtTelNo")) {

		if(document.getElementById("txtTelNo").value == "") {

			alert("Please enter your telephone number");

			return false;

		}

	}

	

	if(document.getElementById("txtTelNo")) {

		if(!isNumeric(document.getElementById("txtTelNo").value)) {

			alert("Please enter a telephone number containing only numbers");

			return false;

		}

	}

	

	if(document.getElementById("txtMobileNo")) {

		if(document.getElementById("txtMobileNo").value != "" && !isNumeric(document.getElementById("txtMobileNo").value)) {

			alert("Please enter a mobile telephone number containing only numbers");

			return false;

		}

	}

	

	if(document.getElementById("txtEmail")) {

		if(document.getElementById("txtEmail").value == "") {

			alert("Please enter your email address");

			return false;

		} else {

			if(!isValidEmail(document.getElementById("txtEmail").value)) {

				alert("Please enter a valid email address");

				return false;

			}	

		}

	}

	

	return true;

}

function isNumeric(strString) {

	var strValidChars = "0123456789+() ";

	var strChar;

	var blnResult = true;

	

	if (strString.length == 0) return false;

	

	//  test strString consists of valid characters listed above

	for (i = 0; i < strString.length && blnResult == true; i++)

	{

		strChar = strString.charAt(i);

		if (strValidChars.indexOf(strChar) == -1) {

			blnResult = false;

		}

	}

	return blnResult;

}

function limitchars(el,num) {

	if(el) {

		if(el.value.length > num) {

			el.value = el.value.substr(0,num);

		}

	}

}